1. Field of the Invention
The present invention relates in general to an automatic door closing system and more particularly to an automatic door latching system for a motor vehicle, which, upon sensing a half-latched condition of the door, automatically makes the door fully latched.
2. Description of the Prior Art
In order to clarify the task of the present invention, one of conventional automatic door latching systems will be described prior to describing in detail the present invention, which is disclosed in Japanese Utility Model First Provisional Publication No. 60-137067.
In the device of the publication, there is used a closing lever for achieving the full-latched condition of the door from the half-latched condition of the same. That is, the closing lever is driven to turn by an electric motor via a worm and a worm wheel. During the turning of the closing lever, the same is brought into abutment with a latch plate (more specifically, an extension of the latch plate) of a door lock device and enforcedly moves the latch plate from a half-latch position to a full-latch position. The closing lever makes one turn in the same direction every time the full-latching of the lock device is carried out. That is, when the closing lever is turned to a rest position, a subsequent turning of the lever starts from the rest position.
However, the conventional device of the publication has the following drawbacks due to its inherent construction.
First, the rest position (or start position) of the closing lever tends to change even slightly each time the lever is turned. This change tends to mistime a subsequent operation of the automatic door latching system.
Second, because the closing lever is turned through about 360 degrees extending beyond a degree which is really needed for moving the latch plate from the half-latch position to the full-latch position, the rotation of the closing lever is very wasteful of space. This induces a bulky construction of the latch device and thus that of the automatic door latching system.